1. Field of the Invention
The present invention relates to a controller that controls an output of an internal combustion engine having a heat generating unit projecting into a combustion chamber
2. Description of Related Art
This kind of controller is shown, for example, in Patent Document 1 (JP-A-H11-82271). The controller has an electrode for ion detection disposed at a tip end of a heat generating unit (glow plug) in a conductive manner with a heating element. The controller determines an existence or nonexistence of a disconnection abnormality of the glow plug based on whether a current flows between the ion detection electrode and an inner wall of a combustion chamber. Thus, the existence or nonexistence of the disconnection abnormality of the glow plug can be determined appropriately.
The above-described structure can detect the disconnection of the glow plug but cannot cope with the disconnection when the disconnection actually arises. That is, when the disconnection arises, there is a possibility that starting cannot be performed unless the glow plug is replaced. Even if the starting is possible, there is a possibility that black lead is discharged because of incomplete combustion.